Control apparatus

ABSTRACT

A COMPOSITE MATERIAL COMPRISING AN ELASTIC MATERIAL IN CONTIGUOUS RELATIONSHIP WITH A MATERIAL HAVING THE PROPERTY OF CREEP UNDER STRESS. THE MATERIAL IS CONTEMPLACED FOR USE IN VARIOUS CONFIGURATIONS TO SERVE A TIME DELAY FUNCTION.

March 16, 1971 R. L. ASKE CONTROL APPARATUS 2 Sheets-Sheet 1 Filed Nov.6. 1968 FIG. 2

INVENTOR. ROBERT L. ASKE ATTORNEY March 16, 1971 Filed NOV. 6. 1968 R.L. ASKE CONTROL APPARATUS FIG. 4

2 Sheets-Sheet 2 HOURS i'NVENTOR. ROBERT L. ASKE ATTORNEY United StatesPatent Ofiice 3,570,280 Patented Mar. 16, 1971 ABSTRACT OF THEDISCLOSURE A composite material comprising an elastic material incontiguous relationship with a material having the property of creepunder stress. The material is contemplaced for use in variousconfigurations to serve a time delay function.

BACKGROUND OF THE INVENTION Field of the invention The present inventionpertains to composite metals and their use as time delay devices.

Description of the prior art Numerous timing devices are well-known inthe prior art wherein spring action is retarded by a damper. A commonexample is the spring-shock absorber combination used on vehicles. Inthis case, the normally fast action of the spring is retarded by theshock absorber characterlstics.

Timing devices utilizing a spring-powered clock escapement are alsowell-known in the art. Again the stored energy of the spring isdissipated at a controlled rate dependent on the clock escapement.

Numerous devices wherein normally fast spring forces are retarded cometo mind; however, each have the disadvantage of requiring two separatecomponents: the spring and a damping device.

It is an object of the present invention to provide a composite materialhaving applicability to time delay devices.

SUMMARY OF THE INVENTION The present invention pertains to the use of acomposite material to provide various timing characteristics in a springdevice. The invention is concerned with a single component to replacespring-damper combinations of the prior art.

The delay spring of the present invention comprises a material ofelastic properties coated with a material having the property of creepunder stress. The property of creep is well-known in metallurgy and isexhibited by materials such as lead, copper, and tin. The particularconfiguration of the device may be varied to satisfy differentrequirements. The inner core is made from a suitable spring materialwhich provides the necessary stress to allow creep to take place in theouter coating. The time delay characteristics are controllable byvarying a number of parameters such as creep material composition anddiameter, core material composition and diameter, length (for linearmotion) or number of turn (for rotational motion), or spring meandiameter.

The invention is contemplated for use with ordnance devices to replacetemperature sensitive chemical timers. A bimetal inner core iscontemplated to provide tempera ture compensation.

The delay spring is desirable over chemical timers in that it may beused more than once. Further, the delay spring will do useful work whileproviding its delay action, as may be required in an ordnance device formechanical arming of a munition.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top view of a timingdevice utilizing the material of the present invention.

FIG. 2 is a vertical sectional view through the timing device of FIG. 1.

FIG. 3 is a section of the delay spring material of the presentinvention as used in the embodiment of FIGS. 1 and 2.

FIG. 4 is a graph representing the performance of a successfulembodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 2, a rotor 2is rotatably mounted on a shaft 3 which is part of a base 1. The rotor 2is secured to the shaft 3 by a C-ring 4. A cam disk 5 is secured to thetop of rotor 2..

Referring to FIG. 1, a top view of the device shown in section view inFIG. 2, a pivoted arm 6 engages a notch in the perimeter of cam disk 5.A second pivoted arm 7 rides on the edge of cam disk 5.

In operation, the rotor 2 is turned in a counterclockwise direction to astarting point where it is held by engaging pivoted arm 6 with the notchin the perimeter of the disk 5. At the initiation of the timingsequence, pivoted arm 6 is pivoted away from the cam disk 5 and the disk5 and rotor 2 are free to turn. The rotor 2 turns in a clockwisedirection at a speed determined by the delay spring characteristicsuntil the disk turns approximately one-half a revolution and the pivotedarm 7 engages the notch, causing a desired response, such as release ofa striker to initiate an explosive detonator.

FIG. 3 illustrates a section of the composite material of the presentinvention as employed in the embodiment of FIGS. 1 and 2. An elasticmaterial 10 is contiguously surrounded by a material 11 having theproperty of creep under stress. Material 10 of FIG. 3 is suitable springmaterial to provide stress to allow creep to take place in the material11. Examples of suitable metals for creep material 11 are lead, tin,solder and copper.

A successful embodiment of the present invention was constructed with aninner core material of .008 inch music wire 7.5 inches in length. Theouter creep mate rial 11 was Kester solder alloy Sn60, .062 inch indiameter and 7.5 inches in length. The spring material was wound in acoil having an outside diameter of .374 inch with an inside diameter of.250 inch. The original number of turns was 7% and the original freelength was .508 inch.

Operation of the spring is shown in the graph of FIG. 4. The curvepresented is the number of turns in the delay spring as a function oftime. Data was taken at +35 degrees Fahrenheit.

The delay spring will tend to return to its original configuration aslong as deformation is within the elastic limits of the inner corematerial and the elastic material exerts enough stress on the creepmaterial.

The properties of the delay spring of the present invention can berealized by many different configurations. It is understood, therefore,that the specific embodiments of my invention shown here are for thepurpose of illustration only, and that my invention i limited only bythe scope of the appended claims.

What is claimed is:

1. Timing apparatus, comprising:

a deformable composite material of an elastic material in contiguousrelationship with a creep material, having a preferred configuration;and

means in operative combination with said composite material forindicating the configuration of said com .4 posite material, wherebysaid composite material, creep material is chosen from the groupconsisting of after deformation within the elastic limits of said lead,tin, copper, and combinations thereof. elastic material, returns to saidpreferred configuration after a predetermined time interval. ReferencesCited if 5 UNITED STATES PATENTS a ase mem er avlng a s a tt ereon;

a rotor rotatably mounted on said shaft; 3283591 11/1966 Green 74 3'5 adelay spring of an elastic material contiguously re- FOREIGN PATENTSlated to a Creep material; and 71, 37 1959 France 2 7 1g2 means engagingsaid spring to said base and said rotor 10 whereby as said rotor isrotated about said base OTHER REFERENCES said spring is stressed andsaid spring tends to return German printed application; Stranmann et aL;1,154; to its unstressed position after a predetermined time Sept 26,1963. mterval- German printed application; Seiler et 211.; 1,179,051;

3. The apparatus of claim 2 where said rotor has a 15 Oct 7, 1964 cavitytherein and said delay spring is located within said cavity a d around aShaft MILTON KAUFMAN, Primary Examiner 4. The timing device of claim 3wherein said first elastle material is a spring metal. US. Cl. X.R.

5. The timing device of claim 3 wherein said second 267-182; l0282

